The present invention relates to electric operators for use with molded case circuit breakers, switches and the like and, more particularly, to mounting assemblies for attaching electric operators to circuit breakers, switches and the like.
Molded case circuit breakers are generally used to provide overcurrent protection for various types of electrical equipment. However, in some applications, it is necessary to control circuit breakers from a remote location. In such applications, electric operators may be provided that are adapted to be mechanically coupled to the operating handle of the circuit breaker. Electric operators typically include an actuator, adapted to be mechanically coupled to a circuit breaker operating handle, for moving the operating handle to an open position or, alternatively, to a closed position; an electric motor for driving the actuator and allowing the circuit breaker to be controlled from a remote location; and some means that allows for manual operation of the actuator in the event of a loss of electric power to the electric motor.
Both solenoid operators and motor operators are known. Examples of solenoid operators for molded case circuit breakers and switches are disclosed in U.S. Pat. Nos. 4,553,115 and 4,642,726. Motor operators for electrical operation of the handles of switches, particularly switches such as circuit breakers and contactors, are well known. Many such devices have an actuator forming a slot that engages the switch handle. Typically, the actuator is mounted on a threaded shaft rotated by an electric motor. It is common for the mounting of the motor operator to the switch to be such that once the motor operator is in place, the switch handle is not accessible for manual operation. In these installations, some form of manual operation is provided, such as a crank that rotates the threaded shaft in place of motor operation.
Both solenoid operators and motor operators are adapted to be rigidly mounted relative to the circuit breaker or molded case switch to facilitate movement of the operating handle. Such operators may either be disposed within the circuit breaker or switch housing or mounted either on the side or in the front of the circuit breaker. Irrespective of the mounting arrangement of the electric operator relative to the circuit breaker or switch, the electric operator must include means for manual operation in the event of loss of electric power to the electric operator.
One motor operator assembly shown in U.S. Pat. No. 5,323,131, includes a motor operator unit hinged at one end to a mounting bracket secured to the switch adjacent to the switch handle so that the motor operator unit may be readily rotated between an operative position in which it engages the switch handle for electrical operation of the switch, and a manual position in which the motor operator is rotated clear of the handle thereby providing direct access to the switch handle for manual operation.
Hinged motor operator mounting assemblies, such as shown in U.S. Pat. No. 5,693,923, have been used to permit access to the circuit breaker handle. Since circuit breakers can be mounted vertically or horizontally, a hinged connection may allow the motor operator to swing into proximity of live electrical conductors connected to the breaker or adjacent breakers, thereby creating an unsafe condition. In addition, if the hinge is positioned improperly due to the orientation of the breaker, excessive force may be placed on the hinge causing it to be damaged.
There is a need for a motor operator mounting arrangement that easily provides direct access to the switch handle for manual operation of the breaker without the disadvantages of a hinged coupling.